<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        td {
            width: 20px;
            height: 20px;
        }
    </style>
</head>

<body>
    <table border="1" style="border-collapse: collapse">
        <tr>
            <td colspan="12"> 1</td>
            <td rowspan="13">2</td>
        </tr>
        <tr>
            <td rowspan="13">4</td>
            <td colspan="10">5</td>
            <td rowspan="11">6</td>
        </tr>
        <tr>
            <td rowspan="11">8</td>
            <td colspan="8">9</td>
            <td rowspan="9"> 10</td>
        </tr>
        <tr>
            <td rowspan="9">12</td>
            <td colspan="6">13</td>
            <td rowspan="7">14</td>
        </tr>
        <tr>
            <td rowspan="7">16</td>
            <td colspan="4">17</td>
            <td rowspan="5">18</td>
        </tr>
        <tr>
            <td rowspan="5">20</td>
            <td colspan="2">21</td>
            <td rowspan="3">22</td>
        </tr>
        <tr>
            <td rowspan="3">24</td>
            <td colspan="">25</td>
        </tr>
        <tr>
            <td colspan="2">23</td>
        </tr>
        <tr>
            <td colspan="4">19</td>
        </tr>
        <tr>
            <td colspan="6">15</td>
        </tr>
        <tr>
            <td colspan="8">11</td>
        </tr>
        <tr>
            <td colspan="10">7</td>
        </tr>
        <tr>
            <td colspan="12">3</td>
        </tr>

    </table>
</body>

</html>